The present disclosure relates to a grapple for handling logs. Moreover, the present disclosure relates to a working machine comprising a grapple. Further, the present disclosure relates to a method for changing the gripping configuration of a grapple.
In a logging industry, a main concern is transportation of logs. Subsequent to log cutting and processing on site, logs are loaded onto vehicles and moved to a processing facility. At the processing facility, the logs are unloaded from vehicles, usually by the use of wheel loaders, and loaded in stacks or in bunkers where they remain until they are picked up for further processing. Additionally, stacked logs may be sorted and/or moved to another location.
Loading, unloading and sorting is usually performed by wheel loaders equipped with dedicated attachments. Such an attachment is generally referred to as a timber grapple or simply a grapple. A grapple generally comprises a base portion, e.g. a frame, and a catch arm that is articulated, i.e. pivotably connected to the base portion. For instance, a grapple may comprise hydraulic cylinders attached to the frame and the catch arm. The purpose of the articulated catch arm is to hold logs by applying contact force from the catch arm and the frame to the logs thus enabling that logs can be moved safely. An example of a grapple is disclosed in CN201124415 Y.
However, a prior art grapple, such as the one disclosed in CN201124415 Y, is often designed for one type of log handling, such as sorting or loading, and this generally renders the grapple unsuitable for other types of log handling operations.
It is desirable to obtain a grapple that is more versatile than the prior art grapples.
As such, the present disclosure relates to a grapple for handling logs. The grapple comprises a base portion connectable to a working machine portion and at least one tine connected to the base portion. The at least one tine has a protruding length from the base portion. The grapple further comprises a catch arm pivotably arranged relative to the base portion.
According to the present disclosure, the grapple can assume configurations with different protruding lengths of the at least one tine.
Grapples, in particular large grapples, i.e. grapples that are adapted to handle a large amount of logs at the same time, can generally be used for at least two different types of log handling operations, viz unloading and sorting.
When unloading logs with a grapple, it is generally preferred that the at least one tine is relatively short in order not to damage the logs or the vehicle onto which the logs are loaded. On the other hand, when sorting logs with a grapple, it is generally preferred that the at least one tine is relatively long such that the tine can slide along the ground so that the grapple can be easily filled when loading from stacks and sorting bunkers.
By virtue of the fact that the grapple according to the present disclosure can have different protruding lengths of the at least one tine, the grapple can be used for both of the above log handling operations. Thus, not only does the grapple according to the present disclosure imply a cost save, since an operator can use one single grapple for both the operations rather than two different grapples, but the above grapple also implies an increase in log handling efficiency since the time required for changing the length of the at least one tine can be made shorter than the time required for changing grapples.
Optionally, the grapple can assume at least two gripping configurations, each one with an open condition and a closed condition, with different protruding lengths of the at least one tine. As such, a change in protruding length is generally initiated by an operator and the grapple configuration with the new protruding length can thereafter generally be used for a work cycle that comprises opening and closing the grapple. For instance, one gripping configuration may be an unloading configuration and another gripping configuration may be a sorting configuration. Generally, the protruding length of a sorting configuration may be larger than the protruding length of the unloading configuration.
Optionally, the grapple is adapted to assume the open condition and a closed condition, respectively, by pivoting the catch arm relative to the base portion.
Optionally, the grapple is adapted to assume the open condition and a closed condition, respectively, without pivoting the base portion relative to the working machine portion. As such, the grapple is optionally not a high lift grapple, i.e. a grapple with two catch arms each one of which being pivotable in relation to a working machine portion to thereby open and close the grapple.
Optionally, at least a portion of the at least one tine is adapted to be movable relative to the base portion for altering the protruding length of the at least one tine.
Optionally, at least a portion of the at least one tine is adapted to be pivotably movable relative to the base portion for altering the protruding length of the at least one tine. The fact that at least a portion of the at least one tine is pivotable implies a compact arrangement by which the protruding length can be altered.
Optionally, at least a portion, preferably all, of the at least one tine is adapted to be translatory movable, preferably rectilinearly movable, relative to the base portion for altering the protruding length of the at least one tine. The fact that at least a portion of the at least one tine is translatory movable implies that at least a portion of the tine may be located in an area protected by the base portion when the tine is in a retracted condition.
Optionally, the grapple further comprises a locking arrangement, adapted to assume at least one locking condition, in which the protruding length cannot be changed, and at least one unlocking condition, in which the protruding length can be changed. By virtue of the locking element, a desired protruding length may be maintained even during use of the grapple.
Optionally, the base portion comprises a base abutment surface and the at least one tine comprises a tine abutment surface, the locking arrangement comprising a locking member, preferably a pin, adapted to abut the base abutment surface and the tine abutment surface when the locking means assumes the locking condition.
Optionally, the base portion comprises abase opening with a base opening rim forming the base abutment surface and/or the at least one tine comprises a tine opening with a tine opening rim forming the tine abutment surface.
Optionally, the grapple comprises means for connecting the catch arm and the at least one tine such that such that a movement of the catch arm relative to the base portion can alter the protruding length of the at least one tine. As such, the pivot motion obtainable for the catch arm, which motion is generally used for opening and closing the grapple, may be used for another purpose, namely to alter the protruding length.
Optionally, the catch arm comprises a catch arm connector and the at least one tine comprises a tine connector. The catch arm connector and the tine connector are adapted to be connected to one another such that a movement of the catch arm relative to the base portion can alter the protruding length of the at least one tine.
Optionally, the grapple further comprises an intermediate connector adapted to connect the catch arm connector to the tine connector, preferably the intermediate connector comprises a pin, a wire and/or a chain. The use of an intermediate connector implies that the catch arm connector to the tine connector need not necessarily be located adjacent to one another in order to be able to alter the protruding length.
Optionally, the grapple further comprises a tine actuator, preferably a hydraulic tine actuator, connecting the at least one tine and the base portion, for altering the protruding length of the at least one tine. A tine actuator can generally be remotely operable. As such, the presence of a tine actuator implies that an operator of a working machine comprising a grapple may alter the protruding length without necessarily having to leave the working machine.
Optionally, the tine actuator is adapted to assume a locking condition preventing displacement of the at least one tine relative to the base portion. The use of the tine actuator as a locking arrangement implies that additional locking means may be omitted.
Optionally, the at least one tine comprises an initial tine portion, adapted to constitute the at least one tine in one condition of the grapple, and a separate tine extension adapted to be releasably attached to the initial tine portion to thereby obtain a new condition of the grapple. The use of a separate tine extension implies a cost efficient way of altering the protruding length.
Optionally, the grapple comprises two or more of the tines.
Optionally, the grapple can assume configurations with different distances between the two or more tines.
A second aspect of the present disclosure relates to a working machine comprising a grapple.
A third aspect of the present disclosure relates to a method for changing the gripping configuration of a grapple. The grapple comprises a catch arm and a base portion for connection to a working machine portion and at least one tine connected to the base portion. The at least one tine has a protruding length from the base portion.
The method according to the third aspect of the present disclosure comprises altering the protruding length of the at least one tine.
Optionally, the catch arm is pivotably arranged relative to the base portion and the step of altering the protruding length of the at least one tine comprises:
connecting a catch arm connector of the catch arm to a tine connector of the at least one tine and
pivoting the catch arm relative to the base portion to thereby alter the protruding length of the at least one tine.
Optionally, the method further comprises connecting the catch arm connector to the tine connector by means of an intermediate connector, preferably the intermediate connector comprises a pin, a wire and/or a chain.
Optionally, the grapple further comprises a tine actuator, preferably a hydraulic tine actuator, connecting the at least one tine and the base, the step of altering the protruding length of the at least one tine comprises actuating the tine actuator to thereby alter the protruding length of the at least one tine.
Optionally, the at least one tine comprises an initial tine portion, adapted to constitute the at least one tine in one condition of the grapple, and a separate tine extension, the step of altering the protruding length of the at least one tine comprises releasably attaching the separate tine extension to the at initial tine portion.